Operation method for gas turbine and control device for gas turbine

Abstract

An operation method for a gas turbine according to at least one embodiment of the present disclosure is an operation method for a gas turbine, including: a step of increasing a co-firing ratio of first fuel the co-firing ratio of which is to be increased and second fuel different from the first fuel. The step of increasing the co-firing ratio includes changing at least either of a turbine inlet temperature or a change rate of the co-firing ratio based on information regarding a relationship between the turbine inlet temperature and the co-firing ratio.

The invention claimed is: 
     
         1 . An operation method for a gas turbine, comprising:
 a step of increasing a co-firing ratio of first fuel supplied from a first fuel supply source, the co-firing ratio of which is to be increased and second fuel supplied from a second fuel supply source different from the first fuel supply source and including fuel component different from the first fuel,   wherein the step of increasing the co-firing ratio includes changing at least either of a turbine inlet temperature or a change rate of the co-firing ratio based on information regarding a relationship between the turbine inlet temperature and the co-firing ratio.   
     
     
         2 . The operation method for the gas turbine according to  claim 1 ,
 wherein the information is information regarding a relationship among the turbine inlet temperature, the co-firing ratio, and a concentration of unburned fuel of the first fuel in a combustion gas.   
     
     
         3 . The operation method for the gas turbine according to  claim 2 ,
 wherein the step of increasing the co-firing ratio includes changing the turbine inlet temperature so that the concentration of the unburned fuel in the combustion gas does not exceed a specified concentration, based on the information.   
     
     
         4 . The operation method for the gas turbine according to  claim 3 ,
 wherein the step of increasing the co-firing ratio includes:
 controlling the turbine inlet temperature such that the turbine inlet temperature becomes a first temperature, if it is determined that the concentration of the unburned fuel does not exceed the specified concentration, based on the information; and 
 controlling the turbine inlet temperature such that the turbine inlet temperature becomes a second temperature higher than the first temperature, if it is determined that the concentration of the unburned fuel is about to exceed the specified concentration, based on the information. 
   
     
     
         5 . The operation method for the gas turbine according to  claim 4 ,
 wherein the step of increasing the co-firing ratio includes:
 setting an increase speed of a flow rate of the first fuel to a first increase speed such that the turbine inlet temperature becomes the first temperature, if it is determined that the concentration of the unburned fuel does not exceed the specified concentration, based on the information; and 
 setting the increase speed of the flow rate of the first fuel to a second increase speed greater than the first increase speed such that the turbine inlet temperature becomes the second temperature, if it is determined that the concentration of the unburned fuel is about to exceed the specified concentration, based on the information. 
   
     
     
         6 . The operation method for the gas turbine according to  claim 4 ,
 wherein the step of increasing the co-firing ratio includes:
 setting a decrease speed of a flow rate of the second fuel to a first decrease speed such that the turbine inlet temperature becomes the first temperature, if it is determined that the concentration of the unburned fuel does not exceed the specified concentration, based on the information; and 
 setting the decrease speed of the flow rate of the second fuel to a second decrease speed less than the first decrease speed such that the turbine inlet temperature becomes the second temperature, if it is determined that the concentration of the unburned fuel is about to exceed the specified concentration, based on the information. 
   
     
     
         7 . The operation method for the gas turbine according to  claim 4 ,
 wherein the step of increasing the co-firing ratio includes:
 setting an increase speed of a flow rate of the first fuel to a first increase speed and setting a decrease speed of a flow rate of the second fuel to a first decrease speed such that the turbine inlet temperature becomes the first temperature while the change rate of the co-firing ratio is maintained at a first change rate, if it is determined that the concentration of the unburned fuel does not exceed the specified concentration, based on the information; and 
 setting the increase speed of the flow rate of the first fuel to a second increase speed greater than the first increase speed and setting the decrease speed of the flow rate of the second fuel to a second decrease speed less than the first decrease speed such that the turbine inlet temperature becomes the second temperature while the change rate of the co-firing ratio is maintained at the first change rate, if it is determined that the concentration of the unburned fuel is about to exceed the specified concentration, based on the information. 
   
     
     
         8 . The operation method for the gas turbine according to  claim 4 ,
 wherein the gas turbine includes a compressor for supplying compressed air to a turbine, and an inlet guide vane for controlling a flow rate of air supplied to the compressor, and   wherein the step of increasing the co-firing ratio includes:
 setting an opening degree of the inlet guide vane to a first opening degree such that the turbine inlet temperature becomes the first temperature, if it is determined that the concentration of the unburned fuel does not exceed the specified concentration, based on the information; and 
 setting the opening degree of the inlet guide vane to a second opening degree less than the first opening degree such that the turbine inlet temperature becomes the second temperature, if it is determined that the concentration of the unburned fuel is about to exceed the specified concentration, based on the information. 
   
     
     
         9 . The operation method for the gas turbine according to  claim 4 ,
 wherein the gas turbine includes a compressor for supplying compressed air to a turbine, an extracted air line for extracting air from the compressor, and a control valve for controlling a flow rate of the compressed air flowing in the extracted air line, and   wherein the step of increasing the co-firing ratio includes:
 setting an opening degree of the control valve to a first opening degree such that the turbine inlet temperature becomes the first temperature, if it is determined that the concentration of the unburned fuel does not exceed the specified concentration, based on the information; and 
 setting the opening degree of the control valve to a second opening degree greater than the first opening degree such that the turbine inlet temperature becomes the second temperature, if it is determined that the concentration of the unburned fuel is about to exceed the specified concentration, based on the information. 
   
     
     
         10 . The operation method for the gas turbine according to  claim 3 ,
 wherein the step of increasing the co-firing ratio includes:
 setting an increase rate of the co-firing ratio to a first increase rate, if it is determined that the concentration of the unburned fuel does not exceed the specified concentration, based on the information; and 
 setting the increase rate of the co-firing ratio to a second increase rate less than the first increase rate, if it is determined that the concentration of the unburned fuel is about to exceed the specified concentration, based on the information. 
   
     
     
         11 . The operation method for the gas turbine according to  claim 10 ,
 wherein the step of increasing the co-firing ratio includes setting the increase rate of the co-firing ratio to a second increase rate which is less than the first increase rate and is not less than a predetermined lower limit value, if it is determined that the concentration of the unburned fuel is about to exceed the specified concentration, based on the information.   
     
     
         12 . The operation method for the gas turbine according to  claim 11 ,
 wherein the step of increasing the co-firing ratio includes setting the increase rate of the co-firing ratio to a second increase rate which is less than the first increase rate and is a positive value not less than the predetermined lower limit value, if it is determined that the concentration of the unburned fuel is about to exceed the specified concentration, based on the information.   
     
     
         13 . The operation method for the gas turbine according to  claim 11 ,
 wherein the step of increasing the co-firing ratio includes setting the increase rate of the co-firing ratio to a second increase rate which is less than the first increase rate and is a negative value not less than the predetermined lower limit value, if it is determined that the concentration of the unburned fuel is about to exceed the specified concentration, based on the information.   
     
     
         14 . The operation method for the gas turbine according to  claim 2 ,
 wherein the information is a map representing the relationship among the turbine inlet temperature, the co-firing ratio, and the concentration of the unburned fuel.   
     
     
         15 . The operation method for the gas turbine according to  claim 14 ,
 wherein the step of increasing the co-firing ratio includes changing the turbine inlet temperature not to enter a region where the concentration of the unburned fuel is relatively high, which is preset in the map.   
     
     
         16 . An operation method for a gas turbine, comprising:
 a step of increasing a co-firing ratio of first fuel supplied from a first supply source, the co-firing ratio of which is to be increased and second fuel supplied from a second fuel supply source different from the first fuel supply source and including fuel component different from the first fuel,   wherein the gas turbine includes a sensor for detecting unburned fuel of the first fuel in a combustion gas, and   wherein the step of increasing the co-firing ratio includes changing at least either of a turbine inlet temperature or a change rate of the co-firing ratio, if it is determined that a concentration of the unburned fuel of the first fuel in the combustion gas, which is detected by the sensor, has increased, based on the concentration.   
     
     
         17 . A control device for a gas turbine, comprising:
 a co-firing ratio control unit configured to increase a co-firing ratio of first fuel supplied from a first fuel supply source, the co-firing ratio of which is to be increased and second fuel supplied from a second fuel supply source different from the first fuel supply source and including fuel component different from the first fuel,   wherein the co-firing ratio control unit is configured to change at least either of a turbine inlet temperature or a change rate of the co-firing ratio based on information regarding a relationship between the turbine inlet temperature and the co-firing ratio, when the co-firing ratio is increased.   
     
     
         18 . The operation method for the gas turbine according to  claim 1 ,
 wherein the first fuel is ammonia,   wherein the second fuel is natural gas.   
     
     
         19 . The operation method for the gas turbine according to  claim 16 ,
 wherein the first fuel is ammonia,   wherein the second fuel is natural gas.   
     
     
         20 . The control device for the gas turbine according to  claim 17 ,
 wherein the first fuel is ammonia,   wherein the second fuel is natural gas.